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Old 28-05-2016, 17:10   #61
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Re: Propane Refrigeration

If the pressurized vessel, containing liquid at high temperature (which may be room temperature, depending on the substance) ruptures, the pressure which prevents the liquid from boiling is lost. If the rupture is catastrophic, where the vessel is immediately incapable of holding any pressure at all, then there suddenly exists a large mass of liquid which is at very high temperature and very low pressure. This causes the entire volume of liquid to instantaneously boil, which in turn causes an extremely rapid expansion. Depending on temperatures, pressures and the substance involved, that expansion may be so rapid that it can be classified as an explosion, fully capable of inflicting severe damage on its surrounding.

Great explanation of the phenomena. Thanks for that. Do you write nooze atricles?
Two big "ifs" and a vessel that can no longer hold pressure and variables of temp, pressure and substance (propane here) and it can be called an explosion.

Now how often did you say that happened aboard a sailboat with propane as a refrigerator component? Or go ahead and add as a cooking component. I am no great internet hunter but when I spent hours looking into boat fires and explosions I could not find but a couple and those were like the one where someone was welding and welded through a propane line and it started a fire.
Please find me were propane leaked and blew up.
I am not ignorant of the the definition and how it works.
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Old 28-05-2016, 17:15   #62
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Re: Propane Refrigeration

The natural gas leak in the house (I bet!) was a long one and no one was home either.

A guy in my town years ago attempted to kill his wife. He tried to pull a Hollywood. He put two propane tanks in the oven and set the timer. The oven turned on, went up in temp and the tanks "exploded" blasting the oven up and starting the kitchen on fire. The house burned up mostly. Only mostly. The people stepped out through a window.
Hollywood fail.
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Old 28-05-2016, 17:16   #63
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Re: Propane Refrigeration

Again.
My point.

Propane is not unsafe for a fridge on a boat.
It just isn't.

You can cook with it too.
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Old 31-05-2016, 13:31   #64
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Re: Propane Refrigeration

Whilst I have a gas stove and am reasonably comfortable with living in a boat with it I would not like to have any gas appliance inside the boat which had the gas on full time and required a pilot light to be burning to ignite the main supply when it turned on, this sounds like a recipe for disaster.


Like a lot of things in our modern technological society gas is only as dangerous as it's allowed to be. I was once employed by a company which owned a gas pipeline. It got a hole in it. To repair the hole they cut out a section of pipe and installed a new piece. They did it whilst the line was kept full of gas kept at very low pressure. They cut the holed section out with oxy acetylene torches and welded the new section in with electric welders. It was all very safe as long as they did not allow the gas to mix with air to form an explosive mixture. They did this by lighting up the gas where it exited from the cut pipeline to ensure that it did not collect anywhere, spectacular but provided one avoided the flame it was harmless.
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Old 31-05-2016, 14:02   #65
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Re: Propane Refrigeration

I'm not so worried about Bleve's from propane on board. Is it possible, Yes. But newer tanks have a safety valve to vent propane should the pressure rise too high.

On a boat for a Bleve to happen, you're going to have a fire or explosion first 99.9 times out of 100 before a bleve. You'll be in the water or dead before a propane tank does a spontaneous rapid disassembly.

A propane fridge from an engineering standpoint, is pretty low on the options list. It made sense 20-30 years ago for RV's but they require the unit to be vertical at all times for the gravity circulation to work.

12V compressors and a solar panel or two should be at the top of the list. Or for the monetarily challenged, a 120V dorm fridge and a cheap $60 MSW inverter. My $200 system still works well after 9 years and 6000 miles.
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Old 31-05-2016, 14:35   #66
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Re: Propane Refrigeration

"The U.S. Consumer Product Safety Commission (CPSC) reports there have been at least 39 incidents in the U.S. involving these old Servel gas refrigerators, causing 22 carbon monoxide-related deaths and 55 injuries nationwide. There also have been incidents reported in Ontario, Canada, causing 60 deaths."

CPSC, Warns That Old Servel Gas Refrigerators Still In Use Can Be Deadly | CPSC.gov

My initial comments in the thread were based on hearing of a number of incidents with deaths in the late 70's and early 80's regarding propane refrigerators.

I stayed at a camp that had one. Two years later at the same camp my friends all almost died except one guy woke up and realized something was drastically wrong. Several ended up having to get treatment for CO poisoning. The chimney was plugged on the refrigerator.
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Old 31-05-2016, 19:39   #67
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Re: Propane Refrigeration

Quote:
Originally Posted by Therapy View Post
If the pressurized vessel

Great explanation of the phenomena. Thanks for that. Do you write nooze atricles?


OMG, nope don't write news stories. Lets try this from basics. You have likely heard or maybe even seen that cavitation damage occurs to propeller blades on power boats? If not just quit here. Ever wonder how air bubbles can damage a metal prop? Likely not, but anyhow, it's because when the area of the prop where the bubbles have formed gets out of the cavitation zone the bubbles collapse. Still with me? The bubbles collapse FAST, the water then rushes in and impacts the metal surface and starts breaking it up, called spalling. Like in overloaded ball bearings. BLEVE: first two words "boiling liquid", meaning bubbles get produced. And like prop cavitation bubbles, they move a ways until they can collapse back and the fluid (sorry, new word, but hang in there) impacts onto the metal surface, breaking it up, So if you believe that cavitation damage really occurs in props, maybe you can believe that it occurs in a tank full of propane? Huh, maybe? And once the inside of that propane tank accumulates enough damage it WILL fracture and blow wide open, release (as you quoted) all the LIQUID propane into vapour, which adds nicely to the fire raging outside.

NO ONE said liquid propane nor liquid gasoline will burn if it leaks. What was said is there is a serious danger of explosion from the vapours of these liquids once the correct air-fuel ratio is reached AND there is a source of ignition. I agree with Sailor Chic, BLEVE's are unlikely but they do happen if a raging fire gets to the tanks. The pressure relief valve is a nice thought, but the pressure that causes the valve to open is caused by boiling of the propane inside.....

Two big "ifs" and a vessel that can no longer hold pressure and variables of temp, pressure and substance (propane here) and it can be called an explosion.
Please find me were propane leaked and blew up.
I am not ignorant of the the definition and how it works.
I'm not going to touch on what you're ignorant of, never was good at making lists anyhow. Let us know how your tests with gas cans and lighters goes however, preferably with a video. Oh, maybe use a metal can, plastic shrapnel doesn't show up as well in an XRay. Bottoms up!
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Old 31-05-2016, 20:01   #68
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Re: Propane Refrigeration

Quote:
Originally Posted by Therapy View Post
Again.
My point.

Propane is not unsafe for a fridge on a boat.
It just isn't.
Succinct, well thought out answer, well presented with significant scientific back up.
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Old 31-05-2016, 20:14   #69
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Re: Propane Refrigeration

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Originally Posted by Greenman View Post
So in a protected anchorage or a dock the fridge may be "okay" but not practical on passage.

Thank you.
Seem to work fine on a catamaran.
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Old 31-05-2016, 20:17   #70
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Re: Propane Refrigeration

Quote:
Originally Posted by Dymaxion View Post
I'm not going to touch on what you're ignorant of, never was good at making lists anyhow. Let us know how your tests with gas cans and lighters goes however, preferably with a video. Oh, maybe use a metal can, plastic shrapnel doesn't show up as well in an XRay. Bottoms up!
I know what happens...sometimes. The ones that make the nooze for sure.

This is pretty old but then gas has not changed too much.

http://fire-exforensics.com/assets/e...fire-myths.pdf
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